Samples from 12 of the corpses were taken for forensic analysis. In at least four cases, scientists found traces of the DNA of the Yersinia pestis, confirming they had contact with the plague prior to their death.

To pinpoint which historical plague outbreak the "Charterhouse 25" could have fallen victim to, the researchers used radio carbon dating.

They determined the burial ground was used in at least two distinct periods - the earliest within the Black Death in 1348-50, followed by a later outbreak in the 1430s.

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The bodies were found in a Crossrail shaft

In a bid to understand just how far the grave extends across the square, Crossrail approached the University of Keele to undertake a forensic geophysics survey - using ground-penetrating radar.

The initial scan detected signs of further burials across Charterhouse Square and also the foundations of a building - possibly a chapel.

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Traces of plague bacteria were found in the teeth of the skeletons

"We will undertake further excavations in Charterhouse Square later this year to confirm some of the results," said Mr Carver.

The skeletons provide a rare opportunity to study the medieval population of London, according to osteologist Don Walker, of the Museum of London Archaeology.

He said: "We can start to answer questions like: where did they come from and what were their lives like?

"I'm amazed how much you can learn about a person who died more than 600 years ago."

Analysis of the skeletons' bones and teeth indicates that:

Many of the skeletons appear to suffer signs of malnutrition and 16% had rickets.

There is a high rate of back damage and strain indicating heavy manual labour.

The later skeletons from the 1400s had a high rate of upper body injury consistent with being involved in violent altercations.

13 of the skeletons were male, three female, two children, the gender was undetermined in the other seven skeletons.

40% grew up outside London, possibly as far north as Scotland - showing that 14th Century London attracted people from across Britain just as it does today.

Mr Carver said: "We can see from the people here that Londoners weren't living an easy life.

"The combination of a poor diet and generally a struggle means they were very susceptible to the plague at that time and that's possibly one of the explanations for why the Black Death was so devastating."

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Archaeologist Jay Carver hopes to explore more of the burial site

By sequencing the ancient bacterial DNA, researchers hope to understand how the plague has evolved and spread over the centuries.

Globally the infection still kills 2,000 people a year, including countries like Madagascar. Antibiotics are available, but if untreated the disease kills within four days.